Does not reproduce the mapping error...

command_sample

$ curl -XPUT localhost:9200/test_idx -d @config.json

{"error":"MapperParsingException[mapping [test_type]]; nested: IllegalArgumentException[Invalid format: [not_analyze]: Illegal pattern component: n]; nested: IllegalArgumentException[Illegal pattern component: n]; ","status":400}jupiter:ess_env 

config.json

{
  "mappings": {
    "test_type": {
      "properties": {
        "title" : {
          "type": "string"
        },
        "timestamp" : {
          "type": "date",
          "format": "not_analyze"
        }
      }
    }
  }
}